The invention relates to exhaust aftertreatment devices, including diesel particulate filter elements and/or catalyst elements, and more particularly to a device evening out the exhaust flow profile across such element.
Exhaust aftertreatment elements typically include an extruded substrate or a spiral wound corrugated or pleated sheet having a plurality of flow channels which may be catalytically treated to provide a flow-through catalytic element and/or which may be alternately plugged at opposite axial ends of the channels to provide a wall-flow filter element. The housing for the element has an upstream inlet for receiving exhaust, and a downstream outlet for discharging the exhaust. The inlet typically has a smaller diameter than the diameter of the housing and aftertreatment element, and exhaust gas entering the housing at the inlet impinges directly at the center of the element, which may cause push-out damage due to concentrated high velocity exhaust gas impinging on the center portion of the catalyst or filter element. The impact force generated from the exhaust flow can often be strong enough to sheer the layers within the spiral wound media and push them out towards the downstream end along the axial centerline.
The present invention addresses and solves the above noted push-out problem with a flow diffuser which de-focuses centralized velocity force flow against the aftertreatment element from the inlet and evens out the exhaust flow profile across such element. In one embodiment, the invention enables more efficient space utilization for contaminant reduction, capture and holding, and also reduces pressure drop. In another embodiment, the invention facilitates cost and manufacturing advantage.